20% of what number is 80? me to understand this ?

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

What is the quotient of m^6/5 ÷ 5/m^2? assume m does not equal pl

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality